president obama will travel to boston tomorrow for an interfaith service to mourn and to pray. he called what happened terrorism. >> this was a han niehaus and cowardly act and given what we now now about what took place, the fbi is investigating it as an act of terrorism. anytime bombs are used to target innocent civilians, it is an act of terror. >> among the dead, 8-year-old martin richard, 29-year-old krystle campbell and the third victim is a boston university grad student from china whose parents asked her name not be made public. let's get to the latest with pete williams. i want to start with the two photos, the before and after of a bag next to a mailbox. how important are investigators thinking these could be? >> to be determined, i think. they are looking at this picture and similar pictures to see if that's how the bombs were placed. they're sort of contradictory photo evidence here about whether that's where they went because the after doesn't seem to show a lot of damage, but it's quite clear that the bombs themselves were not busted up into little tiny pieces and